The invention relates generally to the field of concrete wall stabilization, and more particularly to structures mounted to concrete walls to prevent or mitigate inward movement due to external forces.
It is known in the field of construction and repair of homes and other buildings that basement walls are typically made of concrete. The concrete can be poured as solid walls, or individual concrete blocks can be stacked with mortar placed therebetween to form a wall. Concrete block walls are commonly hollow, but can be filled with concrete and reinforcing rods of metal or other material in order to strengthen the walls and make them less susceptible to the infiltration of water.
Concrete walls of all types are extremely strong in compression, and have disproportionate weakness in tension and shear. This causes concrete walls subjected to substantial tensile and/or shear forces to fracture. A common source of tensile and shear forces in basement walls is a horizontally-directed inward force applied to the walls by the soil that is backfilled against the subterranean walls. This results in a bending force on the walls, which creates a tensile force on the inside of the wall, and causes walls to crack once the force becomes sufficient. Additionally, such inwardly-directed forces can move rows of blocks, or the entire wall, inward in shear from the foundation rather than, or in addition to, causing bowing. This has an obvious deleterious effect on the structural integrity of the building, and can allow water infiltration.
Reduction in horizontal forces can alleviate the bowing of basement walls, and this can be accomplished by reducing water flow into the soil surrounding the building and other methods. Additionally, or alternatively, the walls themselves can be strengthened in order to alleviate bowing and or shearing. Historically, the strengthening of subterranean walls has been accomplished by placing a structural member against the interior surface and bracing that member against other structural members of the building, such as the concrete floor at the base of the bowed wall, and the floor joists at the top of the bowed wall. This can be carried out using simple fasteners, or more complex jacks.
U.S. Pat. No. 6,662,505 to Heady et al., which is incorporated herein by reference, discloses an apparatus for applying a horizontal force at the top of a structural member, such as a steel I-beam. The beam is mounted to the basement floor at its base, and the top is mounted in the apparatus of Heady. Upon the application of force to the top of the beam by screwing in the threaded bolt of Heady's device, the beam is forced against the bowed wall, and exerts a force to the wall that opposes the bowing force.
One disadvantage of the Heady patent and most other conventional wall reinforcement methods of which the inventors are aware is that they do not supply a force against the wall that remains if the soil contracts and the wall moves outward toward the soil. The only alternative in the prior art is to check the force on the beam frequently and manually tighten the screw that applies the force.
U.S. Pat. No. 7,681,367 to the present inventors, which is incorporated herein by reference, addresses the problem of the variations in forces. However, there is a need for other structures that apply a force to a basement or other concrete wall, or at least stop movement of the wall by external forces, along with a means and/or method of preventing or mitigating lower block shear.